Thanks! That perfectly fits to assign to a scalar:

sub setifdef { $_[0] = $_[1] if defined($_[1]) }
setifdef $foo, $bar;

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And in case of a list I'll use the (slightly less readable) 'for grep defined,' psuedo-inline operator. It only makes sense with list references (if you treat (undef) as valid list). Defined scalar values which are transformed to a list can also be handled:

@list = @{$_} for grep defined, $listref_or_undef;
@list = split(",",$_) for grep defined, $splitme_if_defined;

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In reply to Re^2: Assignment to a value only if it is defined by voj
in thread Assignment to a value only if it is defined by voj

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